1. Field of the Invention
The present invention relates to fluid cartridges configured to store fluid, e.g., ink, fuel, gas, or similar fluids, and to fluid amount detections systems configured to detect an amount of fluid in such fluid cartridges.
2. Description of Related Art
A known inkjet recording apparatus performs printing by ejecting ink from a recording head onto a recording medium, and an ink cartridge may be removably mounted to the known inkjet recording apparatus. When a recording head attempts to eject ink from an empty ink cartridge, air may enter into the recording head, which may cause printing failures. Moreover, air entering the recording head may damage the recording head. To reduce the likelihood of such situations occurring, the known inkjet recording apparatus monitors an ink level or an amount of ink in an ink cartridge, and prevents ink ejection from the recording head before the ink in the ink cartridge is depleted.
In the known inkjet recording apparatus, to detect the amount of ink in the ink cartridge, the ink cartridge includes a container formed of a flexible film for storing ink, a case configured to accommodate the container, and a detection plate bonded to a surface of the film of the ink container and configured to slide inside the case. An interior of the container is not in fluid communication with the atmosphere. Therefore, the internal pressure of the container may be reduced as the ink within the container is consumed or reduced. When a difference between the atmospheric pressure and the internal pressure of container reaches or exceeds a threshold value, the film of the container begins deforming in a manner which narrows an interior space of the container. By reducing the volume of the interior space as the ink is depleted, the internal pressure of the interior space of the container may remain constant. As the film deforms, the detection plate bonded to the film of the container moves. By detecting the movement of the detection plate, it is determined that ink within the container is reduced.
Nevertheless, when the amount of ink in the container is sufficiently reduced, the amount of ink in the container may not be accurately determined merely by the detection of the movement of the detection plate.